On complaints from domestic competitors, South Korea's state trade watchdog decided Friday to impose preliminary anti-dumping tariffs on ferro sillico manganese from Vietnam, Ukraine and India.

The Korea Trade Commission proposed temporary duties ranging from 6.08 percent to 32.21 percent, saying the three countries sold ferro sillico manganese, an alloy widely used in iron and steel industries, lower than normal market prices, hurting the South Korean industry.

Products from the three countries accounted for 40 percent of the South Korean market valued. In November last year, three Korean firms including Dongbu Metal filed complaints with the commission which is expected to hand down its final ruling after a three-month probe.

The commission also plans to launch an anti-dumping investigation into polyethylene terephthalate (PET) from Taiwan, Thailand and the United Arab Emirates.